After scale everything else is a toy!

I have seen the Scale mufflers by century and wonder if the muffler will "inhibit" the movement of the slide throttle that is seen on the OS engines. I wondered about the OS .91 in that the exhaust exits to the rear, which will go out the bottom of the helicopter. Would it be possible to mount a "Pitts" typr of muffler and allow it to go straight out the bottom??